Question

I have an array of apps with ids and categories like this:

[apps] => Array
            (
                [0] => stdClass Object
                    (
                        [id] => 0
                        [categoryid] => 0
                    )

                [1] => stdClass Object
                    (
                        [id] => 31265
                        [categoryid] => 12
                    )

                [2] => stdClass Object
                    (
                        [id] => 15965
                        [categoryid] => 2
                    )

                [3] => stdClass Object
                    (
                        [id] => 16554
                        [categoryid] => 12
                    )
)

I am trying to get all apps for a category based on this request. So, the resultant output for:

For CategoryId 12:
----------------
[apps] => Array
            (
                [0] => 31265
                [1] => 16554
            )

For CategoryId 2:
----------------
[apps] => Array
            (
                [0] => 15965
            )

For CategoryId 0:
----------------
[apps] => Array
            (
                [0] => 0
            )

I believe i need to use nested foreach loops, but is there an efficient method?

Thanks

Answer 1

You could cycle through them, and place them into category-arrays:

foreach ( $apps as $app ) {
  $catArray[ $app[CategoryID] ][] = $app;
}

This should result in an array whose key represents a category, and whose nested arrays represent those apps in that category.

I’ve worked up a demo of this online at: http://codepad.org/WZXIvQ58